Brake shoe adjusting mechanism



' Dec. 12, 1944'. I s. sdHNELL BRAKE sHoE AJUsTING MEGHAMSM Filed June 23. '1943 ATTORNEY4 ST E-SCHNELL I I QN. l l.

Patentes Dee. 12, 1944 UNITED" STATES vjl-"A'I'EN'I DFFICE BRAKE SHOE ADJUSTINGTMECHANISM Steve Schnell, Kirkwood, Mo., assigner to Wagner mectrlc Corporation, St. Louis, Mo., a corporation of Delaware Application June 23, 1943, Serial No. 91,917

5 Claims. (Cl. 18S-79.5)

Other objects of my invention will become apjustine' mechanism embodying my invention; and

-Figure 2 is a sectional view showing the parts of being taken brake comprises aI drum i secured to a. shaft 2 and beneath the drum is a base comprising two angle members 3 and l. Pivoted on these angle K members are two levers 5 and 6 carrying brake shoes 'I and 8 provided withnlinings 8 and l0, respectively. Thefupper ends of levers 5 and 8 are connected together by an L-slia lever is pivoted to lever 5 by a pin I3 and one end of linkl I2 is pivote-Hy connected to lever. Q by a, pin I4. The other end of this link isadjustably connected to the toe end ci' lever ll by a sleeve l5 pivoted thereon by a pin i6 and adjustably connected to the link by nuts l1 and I8 tuating leverlll comprises a fluid motor I8 con nected between the free end oi lever Il and lever E, said motor having a'conduit 2li connected to any suitable .source of fluid pressure as, for example, a master cylinder device. 1 A 'retracting spring 2| is connected between lever Il and lever 6.- Y'

' When iiuid under pressure is not being forced'v into the fluid motor I9,` spring 2l will act upon lever H to move levers V,5 and 6 away from the drum and disengage brake shoes] and I. When itis desired no apmy thebrake, uuid under pressure is forced into fluid motor i3, thu; rotating the lever in the direction of the arrow to cause levers 5v and 6 to be moved toward the drum and thereby engage brake shoes l and d. l

In this type of brake it is desirable to maintain a predetermined clearance between one of the ybrake shoes, and the drum when the brake' is I released regardless of Wear of the linings of the brake shoes- Whenthis is done, the other brake shoe will also be maintained clear of the brake drum and will not drag thereon when the brake is not being applied. This is best accomplished by an automatic adjusting means associated with one of the brake shoes. Such an adjusting vmechanism should be easily associated with the brake shoe, readily accessible, and so constructed that it will operate eiiiciently under all conditions, particularly undesirable weather conditions since the industrial brake is generally exposed to rain, snow, ice, dust and other undesirable substances.

The particular adjusting mechanism shown as embodying my invention is generally indicated by the numeral 22 vand is positioned between the base of the brake and lever 5 carrying brake shoe l. This adjusting mechanism is shown in detail in Figure 2 and comprises a cylindrical block 23 pivotally mounted, by a pin 24, between anges 25 of the lever which is o1 U-shaped cross-secnon. secured tonus block is a cylindrical shelf 26 which receives a piston-like member 21 in its inner end for abutment with block 23. This member 21 is secured to theend of rod 28 extending out of shell 2B. The piston memberis confined v ped lever il g and a. link l2. The heel end of, the L-shaped stop member being spaced from block4 23 a vdisl threaded on the link. The control means for acin the shell between block 23 and a stop member 29 welded to the inner surface of the VAshell.- said tance slightly` greater than the length of mem-Y ber 2l to thus provide a clearance 30 determining the amount of relative movement permitted4 between member 2 1 and both V.the shell and the block. This clearance also determines. the

amount of clearance the brake shoe l will have when the brake is in released condition. A spring V3l is interposed between stop 29 and a flange poftion of member 21 in order to bias the member into engagement with block 23.

base. This member 33 is also provided with av bore 34 at right angles to bore: 32, and received in this bore is a pin 35 which acts as a. shaft to pivot member 33 vin bearing openings 36 and 31 of angle members 3 and I. The shaft is provided with a. cross-bore 38 for alsdreoeivins rod v ceives a cylindrical member 4l provided with a Y cally cause rod 28 to be gripped and held in the cross-bore Il havingsuch diameterastosnugly receive rod 2l. VThis cylindrical membris acted Vupon byastrongcoilsprlng 42 interposed between it and a closure plate l! at the outer end of bore 39. The arranmement is such that spring 42 applies pnesslne through member 4l to frictionally hold rod 28 from sliding through bore 8l of shaftvli.- 'Ihe frictional gripping. hOWeVel Yis not great enough to prevent movement of rod 2l with respect to member 23 when the strong Vforce nato apply the brake acts on'the rod in an axial direction.

. when uie brake is in its released emulsion,

partsofthe automatic adJustingwlll assmnethepositionsshowninl'igure2andclearance 3l will-be present between stop 2l and member21. Whenthebrakesareappliedleverlwill bemoved toward thedrum and will carry with Vit block 2l and shell 26 thereby compressing spring liandplacing the clearancebetween block Y28 andfmember 21.- The relative movementA -permitted between member 21 and block 23 by -clearaneellwillpermit shoe1tobeappliedto `thedrum. Whenthebrakeisreleased,theparts will again assume their .positiorm as Vshown in l'lgme2,andmember21wiliactasastopinde proper position by the friction gripping means so I that when the brake is released, the desired shoe clearance is established by the clearance space Il built into the adjusting mechanism.

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principles of my invention, I do not intend that its scope be vlimited except as set forth by the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In braking apparatus, a support, a brake drum, a friction element for cooperation with the drum, means for actuating the friction element, and automatic adjusting means for the friction element for maintaining the oil position clearance thereof substantially constant notwithstanding wear of its friction surface, said adjusting means comprising a member connected to move with the friction element, a rod, means cooperating with the ,last named member and the rodV forV permitting limited relative movement therebetween, a member having a borereceiving the rod, a pivot pin for connecting the last named theo "positionofshoel MemberV z'ienareauwmnoebemuvedxeleavelym member in theha'seof-tbe brakesince the grlppingaction caused byspringwillbegreat enough to prevent .any movemaitof rod'll 'through'springIL Sincebrakesboe lcanvonly bemoved awayfrointhedrumapredetenn'ined distance as determined by the mechanism acting on an abutment for lever l, the actuating leverrli when released, will move shoe l away from the drum and prevent it from drag- The xmvenent 'ot-shoe O'away fromthednnnwillbebrought about'by theaction Vofxetralctingspring2i.

Whenthereis'wearoflining to move closerto the druxn .in order to apply brak'eshoe1.-Whenthistoccurs,stop

2lonshel126willengagemember21andmove rod 2l with respect to member 3l and slide said rod throughtbe frlcidonal gripping means to a newfposition. In this new'podtion the clearanoetlwillremainthesameandwhenthe-shoe is released. its oli position clearance with re- ASpecttothe dium s, levers win have willalsoranainthesameasit' waspriortoliningwear. .Whmevertherehas` been 'such avlarge anmuntfofliningrwear as to cause an undesirable angular movement of leverV Il in applyingthe brake, the connection between rodi! andlever il maybe soasto'bring shoe l closerto the drum and thm shorten the movement of lever "to apply the brake. Y

Y Itis to be noted that in the adjusting mech- .anism just described the paris areall enclosed. No water, snow, or dint can reach the friction gripping mechanism to prevent it from operating inthe desiredmanner.V Also,dirtandotherun desirable -substances are prevented from collecting around the spring Il and betweenlmember 21 and either stop 2! or block 2l tochange theclearance space determining the on position clearance of brakeshoe 1. Iheentire structure of the and as semblemand readily associated with the Nospecialsetting otthesdimtiasmechanism is'required vwhen initially installed as it .needonlybeattachedtotheleverandtbebase member for member tothe support, and means associated ,with the pivot pin for causing the rod to' be fric- -tionally'held in the bore.

2. In braking apparatus,\`a support, a brake drum, a brake friction element for cooperation A with the drum,'means for actuating the friction elementand automatic adjusting meansfor the frictionV element for maintaining the "olf" posi'- tion clearance thereof substantially constant notwithstanding wearof its friction surface, said adlasting means comprising a pivoted member connected to move with the friction element, a cylindrical shell carried by the pivoted member, a

rod positioned in the shell, a spring between the rod and the she11 acting to bias the rod toward -the `pivoted member, means permitting a-predetermined movement of-'said rod relatively to the member and shell and in a direction against; lthe bias of the spring and means carried by the support for frlctionally gripping the 3.'In brakingapparatum-a support, a brake drum, a brake friction .element for cooperation with the drum, means for actuating the'friction element, and automatic adjusting means 'for the friction element formaintaining the of pomtion clearance thereof substantially constant notwithstanding wear of its friction surface, said `adjusting means comprising a pivoted member connectedto -move with the friction element, a cylindrical shell carried by the pivoted member, a

rod positioned inthe shell, a spring between the rod and the shell acting to bias the rod toward lthe pivoted member,V means permitting ,a predetermined movement of said rodrelatively to the member and shell and in a direction against the bias of the spring. a member pivoted to the support and having a bore at rightangles to its piv- 'otal axis'for receiving the rod` and spring-operated means carried by said last named pivoted frictionally holding the rod in the bore.

.4. In braking apparatus. a brake drum, a support having spaced portions extending beneath ,l

pivotally mounted on the support and positioned onv one side of the drum,`

the drum, a brake shoe means for actuating the shoe, and automatic adjusting means between the'support and the shoe termined relative movement between the member and rod, a member positioned between the spaced support portions and pivoted thereto, said member having a bore receiving the rod with the axis of said bore being at right angles to the pivotal` port having spaced portions extending beneath the drum, a brake shoe pivotaily mounted on the support and positioned on one side of the drum.

means, for actuating the shoe, automatic adjusting means between the support and the shoe comprisng a. -pivoted member connected to move with the shoe, a rod, means for permitting predeter.

mined relative movement between the member and rod, a, member positioned between the spaced support portions, a shaft for pivotally mounting 4the last named member on the support portions, said last named member and the shaft being provided with bores receiving the rod, and spring means carried by the shaft for frictionaliy holding the rod in the shaft bore.

STEVE SCHNELL. 

